Compilare: user.cpp: In function ‘void read()’: user.cpp:19:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:21:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &u, &v, &capacity); ^